\part{part}
         part text
         part text
         \chapter{chapter long title}
          chapter text
          chapter text
          \[
          	f(x)=x^2
          \]
          \section[for the toc]{section}
           section text
           section text
          \section[for the toc]{section}
           section text
           section text
          \subsection[for the toc]{subsection}
          	subsection text
          	subsection text
          \subsection[for the toc]{subsection}
          	subsection text
          	subsection text
          \section[for the toc]{section}
           section text
           section text
         \chapter{chapter}
          chapter text
          chapter text
\part{part}
         part text
         part text
         \chapter[toc]{chapter title}
          chapter text
          chapter text
          \section[for the toc]{section}
           section text
           section text
           \subsubsection[for the toc]{subsubsection}
           	subsubsection text
           	subsubsection text
           	\paragraph{paragraph}
           		paragraph text
           		paragraph text
           		\subparagraph{subparagraph}
           			subparagraph text
           			subparagraph text
          \section[for the toc]{section}
           section text
           section text
           \subsubsection[for the toc]{subsubsection}
           	subsubsection text
           	subsubsection text
           	\paragraph{paragraph}
           		paragraph text
           		paragraph text
           		\subparagraph{subparagraph}
           			subparagraph text
           			subparagraph text
         \chapter[somethingelse]{goes here}
